Sear the Chicken: Heat the olive oil in a large, heavy-based ovenproof pan over a medium-high heat. Add the chicken pieces in a single layer—listen for that satisfying sizzle. Cook for 4-5 minutes until the underside is golden brown and releases easily from the pan. Flip and cook the other side. The chicken should be just cooked through and smell deeply savoury. Remove with a slotted spoon and set aside.

Build the Base: Reduce the heat to medium and add the chopped onion and celery. Stir, scraping up any browned bits from the bottom of the pan. Cook for 6-7 minutes until the onion becomes translucent and the celery softens. The kitchen will smell sweet and earthy. Add the garlic and cook for one minute more, until fragrant.

Make the Roux: Sprinkle the flour over the softened vegetables. Stir constantly for two minutes—the mixture will form a thick paste and smell slightly nutty. This is the foundation of your sauce.

Create the Sauce: Slowly pour in the chicken stock, stirring vigorously to prevent lumps. The mixture will thicken immediately. Add the double cream and continue stirring until the sauce is smooth, glossy, and the colour of pale gold. Let it bubble gently for three minutes, then season with smoked paprika, dried thyme, salt, and pepper.

Combine and Simmer: Return the seared chicken to the pan, along with all the corn—both tinned and frozen. Stir everything together until the corn is evenly distributed. The sauce will look creamy and the chicken will be nestled among the sweet yellow kernels. Let it simmer on a low heat for 10 minutes, stirring occasionally, until the flavours have melded and the sauce has thickened slightly.

Prepare the Topping: While the casserole simmers, make the topping. In a bowl, combine the fresh breadcrumbs with the melted butter and grated Parmesan. Use your fingers to mix until the crumbs are evenly coated and feel clumpy and damp. They should smell buttery and savoury.

Assemble and Bake: Preheat your oven to 180°C (160°C fan). Pour the chicken and corn mixture into a 9x13 inch baking dish. Sprinkle the cheesy breadcrumb topping evenly over the surface, covering every bit of the creamy filling. Bake for 25-30 minutes, until the topping is deep golden brown and the sauce is bubbling up around the edges. You'll hear it gently popping as it bakes.

Rest and Serve: Remove the casserole from the oven and let it rest on a wire rack for 10 minutes. This is crucial—it allows the sauce to settle and the topping to set slightly. The aroma at this point is irresistible: buttery, cheesy, and sweet all at once.